Sewing machine feed mechanism



1962 J. M. WASHBURN 3,018,745

SEWING MACHINE FEED MECHANISM Filed Nov. 16, 1959 5 Sheets-Sheet 1IMUQTI/OWZ @FazzM-Wshburm y EWJLW W His-Atorneys Jan. 30, 1962 J. M.WASHBURN 3,018,745

SEWING MACHINE FEED MECHANISM Filed Nov. 16, 1959 5 Sheets-Sheet 2 7 2 6/6 0 F 24 g2 17 I Inve nfior: JbhnMWashhurn Jan. 30, 1962 J. M. WASHBURN3,018,745

SEWING MACHINE FEED MECHANISM Filed Nov. 16. 1959 5 Sheets-Sheet 5 Maw9' I I. 3 'i':

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9/ 2 106 109 v 5 7 7 f r1 n .15- m0 95 21 54 1/ 17-- 89 I07 I; 6 13 105%10/ E '1 13 v {as 83 p mu Inventor: cibll/n MWaskburn B3! M l M HisAttorneys 3,018,745 SEWING MACHINE FEED MECHANISM John M. Washburn, WestHartford, Conn, assignor to The Morrow Machine Company, Hartford, Conn.,a corporation of Connecticut Filed Nov. 16, 1959, Ser. No. 853,356 7Claims. (61. 112-209) This invention relates to sewing machines, andmore particularly to improvements in differential feed mechanism forsewing machines.

A primary object of the invention is to provide differential feedmechanism for a sewing machine in which the difierential feed may bevaried by the operator without interrupting operation of the machine.

It is another object of the invention to provide differential feedmechanism for a sewing machine in which the length of feeding stroke ofone element of the mechanism may be varied with precision over asubstantial range while the machine is in operation.

In the attainment of these objects, the feeding mechanism includes alink oscillated about a pivotal axis by a driving member pivoted to thelink a fixed distance from the pivotal axis. The feed dog is coupled tothe link for adjustment radially of the pivotal axis to thereby vary theamplitude of movement imparted to the feed dog while maintaining theangle of oscillation of the link substantially constant. Preferably theadjustment is effected by shifting the pivotal axis of the link to movethe link and its pivotal connection to the driving member relatively tothe feed dog. The coupling between the link and feed dog is such thatthis adjusting movement can occur, if desired, while the feed mechanismis in operation.

Other objects and features of the invention will become apparent byreference to the following specification and to the drawings.

In the drawings:

FIG. 1 is an elevation view of the left end of a Merrow type sewingmachine which embodies my invention;

FIG. 2 is an elevation view partly in section of the lower portion ofthe machine shown in FIG. 1 with certain overlying elements omitted;

FIG. 3 is a view similar to FIG. 2 but with still more parts omitted,broken away or in section;

FIG. 4 is a view similar to FIG. 3 but with certain elements appearingin a different position than as shown in FIG. 3;

FIG. 5 is a sectional plan detail view of parts shown in FIG. 4,together with manually operable adjusting means;

FIG. 6 is a view similar to FIG. 3 but showing elements ted StatesPatent U that are omitted in FIG. 3 and omitting certain elements thatare shown in FIG. 3;

FIG. 7 is a vertical sectional view on line 7--7 of FIG. 6;

FIG. 8 is a vertical sectional view substantially on line 88 of FIG. 5;

FIG. 9 is a horizontal sectional view substantially on line 99 of FIG.7;

FIG. 10 is a horizontal sectional detail view on line 10-10 of FIG. 5;and

FIG. 11 is a detail view partly in section of certain pivotalconnections.

The sewing machine illustrated in the drawings is similar in manyrespects to the machine disclosed in United States Patent No. 2,769,416,granted November 6, 1956, upon an application of Bernard N. Pierce anddiffers from the machine shown in the Pierce patent by the inclusion ofstructure designed to achieve the above objectives. As in the machineshown in the Pierce patent, the machine of the present applicationincludes a front feed dog F and a rear feed dog R which are respectivelysecured to front and rear feed bars or carriers 1 and 2. Carriers 1 and2 ice are driven from a main drive shaft 3 journaled for rotation in themachine frame 4. Shaft 3 is driven in rotation by conventional mechanismnot shown. Shaft 3 projects outwardly beyond one end of the machineframe and upon the projecting portion of the shaft a pair of eccentrics5 and 6 are formed. The outer end of shaft 3 is threaded as at 7 toreceive a nut 8 which holds blocks 9 (FIGS. 4 and 5) and 10 (FIGS. 6 and9) upon eccentric shaft portion 6.

Feed dog carrier 1 is supported near its rearward end from frame 4 by abracket 17 mounted upon a spacer 18 (see FIG. 7) which is in turn fixedto the end wall of machine frame 4. Spacer 18 is fixedly secured tomachine frame 4 as by screws 19 (FIG. 8) while bracket 17 is bolted tospacer 18 as by bolts 20 (FIG. 5).

Spacer 18 accurately spaces vertical surface 21 of bracket 17 from thevertical end wall 22 (FIG. 8) of machine frame 4. As best seen in FIG.8, feed dog carriers 1 and 2 slideably engage the bearing surfacesdefined by walls 21 and 22 and are thus guided in movement in parallelvertical general planes.

Adjacent its rearward end, front feed dog carrier 1 is formed with ayoke 24 which slideably engages a block 25. Block 25 is supported uponmachine frame 4 by a pin 26 which projects eccentrically from the end ofa member 27 supported in the frame 4 as best seen in FIG. 5. Block 25 issupported for free pivotal movement upon pin 26. By rotation of member27 relative to frame 4, it is believed apparent that the axis of pivotalmovement of block 25 about pin 26 may be varied relative to machineframe 4. A set screw 29 is employed to lock pin 26 in selected positionsof adjustments relative to frame 4. By virtue of the sliding engagementbetween front feed dog carrier 1 and block 25 and by virtue of the freepivotal movement of block 25 about the axis of pin 26, front feed dogcarrier 1 is supported for angular movement about the axis of pin 26 andalso for radial movement relative to the axis of pin 26.

Front carrier 1 is driven in angular oscillation about the axis of pin26 by block 9 which is slideably received within a yoke 30 formed at theforward end of carrier 1. Radial reciprocatory movement of carrier 1relative to the axis of pin 26 is derived from bushing 11 throughstructure to be described below. The net efiect of the snychronizedangular and radial movement of carrier 1 relative to the axis of pin 26is to drive front feed dog F in a motion such that any point on thefront feed dog F moves in a substantially elliptical path when viewed asin FIG. 3. The major axis of this substantially elliptical path extendsgenerally parallel to the upper surface of the work plate 16.Substantially all of the motion of front feed dog F perpendicular to themajor axis of its elliptical path is derived from the angularoscillation of feed dog carrier 1 about the axis 26. Motion of frontfeed dog F having components extending parallel to major axis of theellipse is substantially entirely derived from the eccentricity of thebushing 11 transmitted to the feed dog carrier by structure describedbelow.

Near the rearward end of feed dog carrier 1, is a feed carrier block 31is mounted for pivotal movement upon the carrier by a stud 32 having anenlarged head 33 countersunk within block 31 and secured to feed dogcarrier 1 by a screw 34 (FIGS. 8 and ll). Referring now particularly toFIGS. 3 and 11, a dovetail slot is formed on the side of block 31 remotefrom the feed dog carrier by a stationary abutment 35 and an adjustableabutment or gib 37 secured to block 31 by screw 38 received within anelongated slot 38' in the gib. A slide 41 in the form of a link isslideably received within the dovetail slot of block 31 for longitudinalsliding movement within the slot in a direction which, as best seen inFIG. 3, extends radially of the axis of pivot 32.

Intermediate the ends of link 41, a bolt 43 having a head 44 seated in acounterbore in the sliding link passes through link 41 and is keyedagainst rotation relative to the link as by pin 45. A bushing 46 issecured upon bolt 43 as by nut 47, bushing 46 defining a first pivotalsupport upon the link. At the lower end of the link, pivotal support ismounted upon link 41 and includes a bolt 49, countersunk head 50, key51, bushing 52 and nut 53.

A drive link 54 is journaled at one end upon bushing 46 for pivotalmovement relative to link 41 about the axis of bolt 43. Drive link 54 isjournaled at its other end upon eccentric bushing 11 on drive shaft 3and, in order to provide clearance between feed dog carrier 1 and thelink, link 54 is transversely offset as at 55. From FIG. 3, it isbelieved apparent that if the pivotal axis defined by the assemblyincluding bolt 49 is held stationary, rotation of drive shaft 3 willcause drive link 54 to oscillate link 41 about the axis of bolt 49.

The pivotal assembly including bolt 49 is supported from the machineframe by structure including a rock shaft 60 journaled for rotationwithin a bearing 61 formed in bracket 17. An arm 63 having a hub 64received upon shaft 60 is fixedly secured to the shaft as by set screw65 (FIG. 3) and is journaled at its other end upon bushing 52 on thelower end of link 41. The opposite end of rock shaft 60 projectsoutwardly beyond bracket 17. A lever 67 is formed with an eye 70 towhich peddle chain (not shown) may be attached and is secured at itsopposite end by bolts 71 to a hub block 72 which is in turn clamped uponrock shaft 60 as by screw 73. A flattened portion 74 permits axialadjustment of hub 72 along shaft 60 to assure a snug fit of hubs 64 and72 against the sides of bracket 17 at opposite ends of bearing 61. Bymovement of lever 67, arm 63 may be rotated about the pivotal axis ofrock shaft 60 and to define end limits to such rotation, stop screws 74and 75 are threadably received within hub 72 (FIG. 1) for respectiveengagement for stationary stop pins 76 and 77 fixedly mounted in bracket17. Lever 67 is normally maintained in a position wherein stop screw 74abuts stop pin 76 by a tension spring 78 connected at one end to an eye79 in bracket 17 and at its opposite end to an eye 80 on lever 67. Tofrictionally maintain stop screws 74 and 75 at their adjusted settings,a channel 81 is cut through hub 72 to expose a portion of the stopscrews in a manner as shown in FIG. 10. A leaf-spring 82 is clamped tothe bottom of channel 81 as by screw 83 to resiliently bear against thesides of both stop screw 74 and stop screw 75 to resist unintentionalturning movement of the screws.

The structure for supporting the rear feed dog carrier 2 is best shownin FIGS. 6, 7 and 9. Near its forward end, rear feed dog carrier 2 isformed with yoke 90 which slideably engages block mounted on eccentric5. The rearward end of carrier 2 is supported upon a link 91 receivedwithin a channel 92 formed in spacer 18 as best seen in FIGS. 6 and 9. Apin 94 riveted as at 95 to the rearward end of carrier 2 pivotallycouples the carrier to the upper end of link 91 while the lower end ofthe link is supported upon an eccentric pin 99 mounted at the outer endof a rotatable stud 97 supported within bracket 17. A groove 100 isformed upon stud 97 to receive the point of a set screw 101 threadedinto bracket 17 whereby stud 97, and-hence said eccentric portion 99 maybe adjustably positioned with respect to the fixed elements of themachine. The structure for supporting the lower end of link 91 issimilar to and analogous in function to the structure which supportsblock 25 upon machine frame 4 as described in connection with front feeddog carrier 1.

A drive link 105 is journaled at one end upon eccentric 12 and ispivotally coupled at its other end directly to feed carrier 2 by apivotal connection including a bushing 106 held upon carrier 2 as by anut and bolt assembly 107l08. Because of the fact that bushing 106 mustpass across the space occupied by drive link 54, an open- 4 ing 109 iscut through drive link 54 to provide clearance for bushing 106.

As is the case with feed dog carrier 1, rear feed dog carrier 2 isdriven in a motion which finds any point upon rear feed dog carrier Rbeing moved in a substantially elliptical path. Again the ellipticalpath in which the feed dog moves has its major axis extendingsubstantially parallel to the adjacent surface of work plate 16,movement of the feed dog along the major axis of the substantiallyelliptical path being derived primarily from drive link while movementalong the minor axis of the elliptical path is derived primarily fromblock 10. From the foregoing description, it will be noted that bothfeed dog carriers 1 and 2 have their rearward ends located with respectto the frame for pivotal movement about an axis whose location withrespect to the frame is adjustable. In the case of feed dog 1, pin 26 ismounted eccentrically upon the end of the member which is rotatablewithin the frame. Rotation of member 27 within the frame raises orlowers pin 26, thereby raising or lowering the pivotal axis about whichthe rear portion of feed dog carrier 1 is constrained to move. Raisingmovement of the axis of pivot pin 26 tends to lower the location of theelliptical path of front feed dog F with respect to the frame, andparticularly with respect to the surface of work plate 16. As thelocation of the elliptical path is lowered, that portion of the pathduring which front feed dog F projects above the upper surface of workplate 16 is decreased. Likewise, lowering movement of the axis of pin 26elevates the path of front feed dog F and a greater portion of theelliptical path projects above the plane of work plate 16. This actionhas the effect of varying the effective length of the feeding stroke offront feed dog F. A similar action occurs with rear feed dog R uponadjustment of stud 97. By adjusting the relative length of the effectivestrokes of the front and rear feed dogs F and R, a differential feed isachieved in a manner familiar in the art;

It is often desirable to change the differential feed during differentportions of a sewing operation upon the same piece of material.Adjustment of the differential feed by adjustment of pivot pins 26 and99 is conventionally performed While the machine is not operating. In asense, the adjustments provided by pins 26 and 99 may be said to beinitial settings. Variation of the differential feed may be accomplishedwhile the machine is in operation by operation of lever 67 to rotaterock shaft 60 with respect to the frame.

In FIGS. 3 and 4, arm 63 is shown in the respective positions it wouldassume at each of its rotative end limits. In FIG. 3, the axis of bolt43 is located approximately midway between the axes of bolts 49 andpivot pin 32. In FIG. 4, at the opposite end limit of movement of arm63, the axes of bolt 43 and pin 32 may be assumed to be in coincidence.

Referring now to FIG. 4, rotation of drive shaft 3 causes link 54 todrive link 41 in pivotal oscillation about the axis of bolt 49. The axisof the bolt 43 is thus driven along an arcuate path concentric to theaxis of bolt 49 and this motion is of a fixed amplitude. Since the axisof pin 32 is coincident with the axis of bolt 43, the amplitude ofmotion imparted to pin 32 through block 31 is equal to the amplitudeof'motion imparted to bolt 43 by the oscillation of drive link 54. Thisis because the radial distance between the axis of bolt 43 and the axisof bolt 49 is equal to the radial distance between the axis of pin 32and bolt 49.

In FIG. 3 arm 63 has been located to a position which will be assumed tobe at its opposite end limit. In this case, the radial distance betweenthe axis of bolt 49 and the axis of pin 32 is approximately twice asgreat as the radial distance between the axis of bolts 49 and 43. Thusthe circumferential motion of link 41 at the radius corresponding to theradial distance between the axis of bolt 49 and the axis of pin 32 isapproximately twice as great asthe amplitude of motion of link 41 at theradius corresponding to the radial distance between the axis of bolts 49and 43. Since the motion imparted to feed dog 41 by drive link 54establishes for all practical purposes the length of the major axis ofthe elliptical path of feed dog carrier 1 when arm 63 is in the FIG. 3position is approximately twice as great as the amplitude of theelliptical path when arm 63 is in the FIG. 4 position.

The arcuate amplitude of oscillation of link 41 about bolt 49 issubstantially constant regardless of the position of arm 63 since theradial distance between bolts 49 and 43 is fixed and unvarying. Thus theamplitude of motion imparted to feed dog carrier 1 is directlyproportional to the radial distance between the axis of bolt 49 and pin32 divided by the radial distance between the axis of bolt 49 and theaxis of bolt 43. This arrangement has the advantage that a given amountof movement of slide 41 by an angular adjustment of 'arm 63 results in achange in amplitude of the major axis of the elliptical path of frontfeed dog F which is directly proportional to the adjusting movement oflink 41.

It is further believed to be apparent that the abovementioned exemplarylimits of adjustment may be varied within practical ranges. For example,if adequate clearance is provided, link 41 may be moved to a positionwherein the radial distance between pin 32 and bolt 49 was less than thedistance between bolt 49 and bolt 43, thus making the magnificationfactor less than 1. Within limits, the magnification factor may also beincreased above two. The particular arrangement also has the advantagein that it is not possible to inadvertently shift the adjustment to aposition wherein the theoretical amplitude of feed dog carrier 1 wouldbecome infinite. Over the range of adjustment provided, the change inamplitude of movement of feed dog carrier 1 is directly proportional tothe magnitude of the adjustment input, thus affording an extremelyprecise control over the adjustment. With this particular structuralarrangement, it is immaterial whether the adjustment is made while themachine is stopped or made while the machine is running at full speed.

While I have described one exemplary embodiment of my invention it willbe apparent to those skilled in the art that the foregoing embodimentmay be modified. Therefore, the foregoing description is to beconsidered exemplary rather than limiting and the true scope of theinvention is that defined in the following claims.

I claim:

1. In a sewing machine having a frame, first support means on said framedefining a first pivotal axis, a feed dog carrier supported at one endupon said first support means for angular and radial movement relativeto said first axis, drive means for driving said carrier in angularoscillation about said first axis, second support means on said framedefining a second pivotal axis parallel to said first axis, a linksupported at one end on said second support means for pivotal movementabout said second axis, means connected between said drive means andsaid link for oscillating said link in pivotal movement of constantamplitude about said second axis in synchronism with the angularoscillations of said carrier about said first axis, coupling meansconnecting said link to said carrier for pivotal movement relative tosaid carrier about a third axis extending parallel to said first axis ata fixed location on said carrier and for sliding movement relative tosaid carrier radially of said third axis to oscillate said carrierradially of said first axis when said link is pivotally oscillated aboutsaid second axis with an amplitude of radial oscillation proportional tothe distance between said second axis and said third axis, and means forshifting said second support means relative to said frame to vary thedistance between said second axis and said third axis to thereby varythe amplitude of radial oscillation of said carrier.

2. In a sewing machine having a frame, first support 6 7 means on saidframe defining a first pivotal axis, a feed dog carrier supported at oneend upon said first support means for angular and radial movementrelative to said first axis, drive means for driving said carrier inangular oscillation about said first axis, second support means on saidcarrier defining a second pivotal axis on said carrier parallel to saidfirst axis, a link received by said second support means for angular andradial movement relative to said second axis, third support means onsaid frame defining a third pivotal axis parallel to said first axis,means coupling one end of said link to said third support means forpivotal movement about said third axis, means coupled to said drivemeans and said link for driving said link in pivotal oscillation ofconstant amplitude about said third axis in synchronism with the angularoscillation of said carrier about said first axis, said second supportmeans transforming pivotal oscillation of said link about said thirdaxis into radial oscillation of said carrier relative to said firstaxis, and means for shifting said third axis toward and away from saidsecond axis to thereby vary the amplitude of radial oscillations of saidcarrier.

3. In a sewing machine having a frame, first support means on said framedefining a first pivotal axis, an. elongate feed dog carrier supportedat one end upon said support means for angular and radial movementrelative to said first axis, drive means for driving said carrier inangular oscillation about said first axis, a block mounted upon saidcarrier for pivotal movement about a second axis parallel to said firstaxis, an elongate link slideably received within said block forlongitudinal sliding movement relative to said block radially of saidsecond axis, second support means upon said frame defining a thirdpivotal axis parallel to said first axis, means coupling one end of saidlink to said second support means for pivotal movement about said thirdaxis in an are having a substantial component longitudinally of saidcarrier, means coupled to said drive means and said link for drivingsaid link in pivotal oscillation of constant amplitude about said thirdaxis in synchronism with the angular oscillation of said carrier aboutsaid first axis, and means for shifting said second sup ort means towardand away from said block to slide said elongate link longitudinallywithin said block to thereby varv the radial distance between said thirdaxis and said second axis.

4. In a sewing machine having a frame, first support means on said framedefining a first pivotal axis, an elongate feed dog carrier supportedadjacent one end upon said first support means for angular and radialmovement relative to said first axis, drive means for driving saidcarrier in angular oscillation about said first axis, a block mountedupon said carrier for pivotal movement about a second axis parallel tosaid first axis, means on said block defining a link receiving slotextending across said block in a direction radially of said second axis,an elongate link received within said slot for longitudinal slidingmovement, a first pivot adjacent one end of said elongate link and asecond pivot on said elongate link intermediate the ends thereof, saidfirst and said second pivots being parallel to each other and said firstpivotal axis, second support means on said frame spaced transversely ofsaid carrier from said block and connected to said first pivot to couplesaid elongate link to said frame, drive link means connected to saidsecond pivot and to said drive means for oscillating said elongate linkin pivotal movement of constant amplitude about said first pivot insynchronism with the angular oscillation of said carrier about saidfirst axis, that portion of said elongate link received within said slotbeing driven in an arcuate path about said first pivot having asubstantial component of motion longitudinally of said feed dog carrierwhereby pivotal movement of said link about said first axis drives saidcarrier in radial movement relative to said first axis, and means forshifting said second support means relative to said frame to vary theradial distance between said first pivot and second axis to thereby varythe amplitude of radial movement of said carrier while maintaining aconstant amplitude of pivotal movement of said elongate link about saidfirst pivot.

5. In a sewing machine having a frame, first support means on said framedefining a first pivotal axis, a feed dog carrier supported adjacent oneend upon said first support means for angular and radial movementrelative to said first axis, a drive shaft journaled for rotation withinsaid frame, a pair of eccentrics on said drive shaft, means adjacent theother end of said carrier coupling said carrier to one of saideccentrics to oscillate said carrier in angular movement about saidfirst axis, upon rotation of said drive shaft, second support means onsaid carrier defining a second pivotal axis fixed with respect to saidcarrier and extending parallel to said first axis, a link received bysaid second support means for angular and radial movement relative tosaid second axis, third support means on said frame defining a thirdpivotal axis parallel to said first axis, means coupling one end of saidlink to said third support means for pivotal movement about said thirdaxis, a drive link coupled at one end to said link for pivotal movementrelative to said link about a fourth axis located intermediate the endsof said link, means coupling the other end of said drive link to theother of said eccentrics to oscillate s aid link in pivotal movementabout said third axis upon rotation of said shaft, and means forshifting said third support means relative to said frame to vary thedistance beween said second axis and said third axis.

6. In a sewing machine having a frame, a feed mechanism comprising afeed dog carrier, means supporting said carrier on said frame forangular and radial movement relative to a carrier axis, a driving link,a pivotal support for said link, a driving member pivotally connected tosaid link at a point spaced from said pivotal support for oscillatingsaid link about the pivotal axis of said pivotal support, means couplingsaid carrier to said link for imparting movement to said carrierradially of said carrier axis upon angular oscillation of said linkabout said pivotal axis and permitting movement of said link relative tosaid carrier in a direction radially of said pivotal axis, and means forshifting said pivotal support to adjust the distance between saidcoupling and said pivotal support to vary the amplitude of radialmovement imparted to said carrier by oscillation of said link withoutchanging the amplitude of angular oscillation of said link.

7. Sewing machine feed mechanism including in com bination, a rotaryshaft, a pair of eccentrics carried upon said shaft, a feed dog carriersupported for oscillatory and reciprocatory movement and embracing oneof said eccentrics, a block having pivotal connection with said carrier,said block being formed with a guideway, a lever slideably mounted insaid guideway, said lever having thereon a first and second pivotal studdefining axes spaced a fixed distance from each other, a link having oneend embracing the other of said eccentrics and its other end connectedto said lever at one of said pivotal studs thereon for oscillating saidlever about the other pivotal stud to impart reciprocatory movement tosaid carrier, and means coupled to the other of said pivotal studs formoving said lever to change the distance between one of said pivotalstuds on said lever and the pivotal connection between said carrier andsaid block, thereby to vary the amplitude of reciprocatory movementimparted to said carrier.

References Cited in the file of this patent UNITED STATES PATENTS1,069,363 Weis Aug. 5, 1913 1,856,360 Thompson May 3, 1932 2,009,747Sauer July 30, 1935 2,341,448 Knaus Feb. 8, 1944 2,546,939 Breul Mar.27, 1951 2,771,848 Knaul et al Nov. 27. 1956

